Continuously variarble transmission

ABSTRACT

A continuously variable transmission for a vehicle includes a drive clutch, a driven clutch operably coupled to the drive clutch, and a belt extending between the drive and driven clutches. The continuously variable transmission also includes an inner cover and an outer cover removably coupled to the inner cover. At least one of the inner and outer covers includes an air inlet for providing cooling air to the drive and driven clutches and the belt.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/644,717, filed Mar. 19, 2018, and is co-filedwith U.S. patent application Ser. No. ______, filed Mar. 18, 2019, thecomplete disclosures of which are expressly incorporated by referenceherein.

FIELD OF THE DISCLOSURE

The present invention relates generally to a transmission for a vehicleand, in particular, to ducting for a continuously variable transmissionon a utility vehicle.

BACKGROUND OF THE DISCLOSURE

Some vehicles such as utility vehicles, all-terrain vehicles, tractors,and others include a continuously variable transmission (“CVT”). The CVTincludes a drive clutch, a driven clutch, and a belt configured torotate between the drive and driven clutches. The position of the driveand driven clutches may be moved between a plurality of positions whenthe vehicle is operating.

Available space is often limited around the CVT which may make itdifficult to service various component of the CVT, for example the belt.Additionally, the intake duct and the exhaust duct of the CVT must bepositioned to receive appropriate air flow to cool the components withina housing of the CVT. Therefore, it is necessary to appropriatelyconfigure a CVT for sufficient air flow within the housing and for easeof serviceability and maintenance.

SUMMARY OF THE DISCLOSURE

In one embodiment of the present disclosure, a continuously variabletransmission (“CVT”) for a vehicle comprises a drive clutch, a drivenclutch operably coupled to the drive clutch, and a housing generallysurrounding the drive and driven clutches. The housing includes an innercover having a first air inlet and an outer cover removably coupled tothe inner cover and having a second air inlet.

In another embodiment of the present disclosure, a powertrain assemblyfor a vehicle comprises a prime mover, a shiftable transmission operablycoupled to the prime mover, and a continuously variable transmission(“CVT”) operably coupled to the prime mover and the shiftabletransmission. The CVT comprises a drive clutch, a driven clutch operablycoupled to the drive clutch, a belt extending between the drive anddriven clutches, and a housing generally surrounding the drive anddriven clutches. The housing includes an inner cover and an outer coverremovably coupled to the inner cover. The powertrain assembly furthercomprises a bearing housing positioned intermediate a portion of theprime mover and the CVT and which is removably coupled to the CVT andremovably coupled to at least one of the prime mover and the shiftabletransmission.

In a further embodiment of the present disclosure, a continuouslyvariable transmission (“CVT”) for a vehicle comprises a drive clutch, adriven clutch operably coupled to the drive clutch, and a housinggenerally surrounding the drive and driven clutches. The housingincludes an inner cover and an outer cover removably coupled to theinner cover. A radial distance between a peripheral surface of the innercover and a radially-outermost surface of the driven clutch increases ina direction of air flow.

A continuously variable transmission (“CVT”) for a vehicle comprisesdrive clutch including a moveable sheave and a stationary sheave, adriven clutch operably coupled to the drive clutch and including amoveable sheave and a stationary sheave, and a housing generallysurrounding the drive and driven clutches. The housing includes a singleair inlet and a single air outlet. The housing is configured to flow airfrom a position adjacent the stationary sheave of the driven clutch to aposition adjacent the stationary sheave of the drive clutch.

A continuously variable transmission (“CVT”) for a vehicle comprises adrive clutch and a driven clutch operably coupled to the drive clutch.The driven clutch includes a moveable sheave and a stationary sheave,and the stationary sheave includes a plurality of fins extending axiallyoutward and an angular distance between adjacent fins of the pluralityof fins is less than 15 degrees.

A continuously variable transmission (“CVT”) for a vehicle comprises adrive clutch including a moveable sheave and a stationary sheave and adriven clutch operably coupled to the drive clutch and including amoveable sheave and a stationary sheave. The CVT further comprises ahousing generally surrounding the drive and driven clutches andincluding an inner cover and an outer cover. The inner cover includes atleast one volute and a channel configured to cooperate with the at leastone volute to direct air within the housing toward the driven clutch.

A continuously variable transmission (“CVT”) for a vehicle comprises adrive clutch including a moveable sheave and a stationary sheave and adriven clutch operably coupled to the drive clutch and including amoveable sheave and a stationary sheave. The CVT further comprises ahousing generally surrounding the drive and driven clutches andincluding an inner cover and an outer cover. The outer cover includes achannel configured to direct air toward the drive clutch.

A continuously variable transmission (“CVT”) for a vehicle comprises adrive clutch including a moveable sheave and a stationary sheave and adriven clutch operably coupled to the drive clutch and including amoveable sheave and a stationary sheave. The CVT further comprises ahousing generally surrounding the drive and driven clutches andincluding an inner cover and an outer cover. A distance between anoutermost surface of the stationary sheave of the driven clutch and aninnermost surface of the outer cover is approximately constant along aportion of the outer cover.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this invention, and the mannerof attaining them, will become more apparent and the invention itselfwill be better understood by reference to the following description ofembodiments of the invention taken in conjunction with the accompanyingdrawings, where:

FIG. 1 is a front left perspective view of a utility vehicle of thepresent disclosure;

FIG. 2 is a front perspective view of a powertrain assembly of thevehicle of FIG. 1;

FIG. 3A is a front perspective view of a continuously variabletransmission (“CVT”) of the powertrain assembly of FIG. 2;

FIG. 3B is a front perspective view of the CVT of FIG. 3A with analternative outer cover or housing and an alternative intake duct;

FIG. 4A is a rear perspective view of the CVT of FIG. 3A;

FIG. 4B is a rear perspective view of the CVT of FIG. 3B with a debrisshield configured to be coupled to the outer housing of the CVT;

FIG. 5 is an exploded view of the CVT of FIG. 3A;

FIG. 6A is a front right perspective view of a drive clutch, a drivenclutch, and a belt of the CVT of FIG. 5;

FIG. 6B is a cross-sectional view of a plurality of fins of the driveclutch, taken through line 6B-6B of FIG. 6A;

FIG. 6C is another cross-sectional view of another plurality of fins ofthe drive clutch, taken through line 6C-6C of FIG. 6A;

FIG. 7 is a cross-sectional view of the CVT of FIG. 3A, taken along line7-7 of FIG. 3A;

FIG. 8 is an exploded view of an inner cover and an internal diverterplate of a housing of the CVT of FIG. 3A;

FIG. 9 is an exploded view of the inner cover and an outer cover of thehousing of the CVT of FIG. 3A and including an illustrative air flowpath through the housing;

FIG. 10 is a cross-sectional view of the CVT of FIG. 3A, taken alongline 10-10 of FIG. 3A;

FIG. 11A is a front perspective view of a further powertrain assembly ofthe vehicle of FIG. 1;

FIG. 11B is an exploded view of a CVT and bearing housing of thepowertrain assembly of FIG. 11A;

FIG. 11C is a rear perspective view of the CVT and bearing housing ofFIG. 11B;

FIG. 11D is a rear perspective view of the CVT housing and analternative bearing housing;

FIG. 11E is an exploded view of a carrier bearing assembly of thebearing housing of FIG. 11D;

FIG. 11F is a cross-sectional view of the transmission and carrierbearing assembly of FIG. 11D;

FIG. 11G is a detailed cross-sectional view of the carrier bearingassembly of FIG. 11F;

FIG. 12 is a front perspective view of a CVT of the powertrain assemblyof FIG. 11A;

FIG. 13 is a rear perspective view of the CVT of FIG. 12;

FIG. 14A is an exploded view of the CVT of FIG. 12;

FIG. 14B is an exploded view of the CVT of FIG. 12 with an alternativeouter cover or housing;

FIG. 15 is a front perspective view of a drive clutch, a driven clutch,and a belt of the CVT of FIG. 14A;

FIG. 16 is a cross-sectional view of the CVT of FIG. 12, taken alongline 16-16 of FIG. 12;

FIG. 17 is an exploded view of an inner cover and an internal diverterplate of a housing of the CVT of FIG. 12;

FIG. 18A is an exploded view of the inner cover and an outer cover ofthe housing of FIG. 14A and including an illustrative air flow paththrough the housing;

FIG. 18B is an exploded view of the inner cover and outer cover of thehousing of FIG. 14B and including an illustrative air flow path throughthe housing;

FIG. 19 is a cross-sectional view of the CVT of FIG. 12, taken alongline 19-19 of FIG. 12; and

FIG. 20 is a cross-sectional view of the CVT of FIG. 12, taken alongline 20-20 of FIG. 12.

Corresponding reference characters indicate corresponding partsthroughout the several views. Unless stated otherwise the drawings areproportional.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments disclosed below are not intended to be exhaustive or tolimit the invention to the precise forms disclosed in the followingdetailed description. Rather, the embodiments are chosen and describedso that others skilled in the art may utilize their teachings. While thepresent disclosure is primarily directed to a utility vehicle, it shouldbe understood that the features disclosed herein may have application toany vehicle with one or more ground-engaging members and a continuouslyvariable transmission, including, but not limited to, all-terrainvehicles, motorcycles, snowmobiles, scooters, three-wheeled vehicles,and golf carts.

Referring to FIG. 1, an illustrative embodiment of a utility vehicle 2is shown. Vehicle 2 is configured for off-road operation. Vehicle 2includes a plurality of ground-engaging members 4, illustratively frontwheels 6 and rear wheels 8. In one embodiment, one or more ofground-engaging members 4 may be replaced with tracks, such as theProspector II Tracks available from Polaris Industries, Inc., located at2100 Highway 55 in Medina, Minn. 55340 or non-pneumatic tires, such asthose shown in U.S. Pat. Nos. 8,176,957 and 8,104,524, the completedisclosures of which are expressly incorporated herein by reference.

Vehicle 2 further includes a lower frame assembly supported byground-engaging members 4, which extends along a longitudinal axis L ofvehicle 2. Additionally, in one embodiment, vehicle 2 may include anupper frame assembly 10 extending vertically above the lower frameassembly, however, alternative embodiments of vehicle 2 may not includeupper frame assembly 10. The lower frame assembly supports a rear cargoarea 12 and a vehicle body 14, which includes a plurality of bodypanels.

Vehicle 2 also includes an open-air operator area 20 which,illustratively, includes seating 22 for one or more passengers. As such,operator area 20 is exposed to ambient air and is not fully enclosed.Alternatively, vehicle 2 may include a cab assembly (not shown), such asa roof, front windshield, rear windshield, and doors, to encloseoperator area 20. Upper frame assembly 10 may be positioned generallyaround operator area 20 such that seating 22 is at least partiallysurrounded by upper frame assembly 10. Illustratively, seating 22includes an operator seat and a passenger seat, however, seating 22 mayalso include rear seats for additional passengers or may include only asingle seat for carrying the operator. Seating 22 may include a seatback 24 and a seat bottom 26.

Operator area 20 further includes a plurality of operator controls 28,such as a steering wheel 16, by which an operator may provide inputs foroperating vehicle 2. Various operator controls, including the steeringassembly, may be further described in International Patent ApplicationNo. PCT/US 13/64516, filed on Oct. 11, 2013 (Attorney Docket No.PLR-15-25448.04P-WO), the complete disclosure of which is expresslyincorporated by reference herein.

Referring still to FIG. 1, vehicle 2 includes a rear suspension assembly18 and a front suspension assembly 19, both supported by the lower frameassembly. Additional details of rear and front suspension assemblies 18,19 may be disclosed in U.S. Pat. No. 9,566,858, issued on Feb. 14, 2017(Attorney Docket No. PLR-15-26601.01P) and U.S. Patent Application Ser.No. 62/608,952, filed Dec. 21, 2017 (Attorney Docket No.PLR-15-28340.02P), the complete disclosures of which are expresslyincorporated by reference herein.

Referring to FIG. 2, vehicle 2 further includes a powertrain assembly 30which is supported by the lower frame assembly and includes at least aprime mover, illustratively an engine 32, a geartrain (not explicitlyshown) which may be configured as a shiftable transmission, and acontinuously variable transmission (“CVT”) 34. Engine 32 is positionedrearward of operator area 20. While the prime mover is disclosed asengine 32, the prime mover may be any type of device configured toprovide power to vehicle 2, such as an electric motor, a fuel-basedengine, a hybrid engine, a generator, etc. In one embodiment, CVT 34also is positioned at least partially rearward of operator area 20. Asshown in FIG. 2, CVT 34 is positioned laterally outward from or to theside of engine 32 in a direction generally perpendicular to alongitudinal axis L of vehicle 2 (FIG. 1) and extends generally parallelto longitudinal axis L. More particularly, CVT 34 is positioned alongthe left side of vehicle 2. In alternative embodiments, CVT 34 mayextend in a generally perpendicular direction relative to longitudinalaxis L or may be configured in any orientation relative to longitudinalaxis L, engine 32, and the geartrain. For example, in one embodiment,CVT 34 may be positioned longitudinally forward of engine 32 andconfigured to extend laterally in a direction generally perpendicular tolongitudinal axis L.

As shown in FIG. 4A, CVT 34 is coupled to both engine 32 and thegeartrain with mounting posts or fasteners 36 which are received withinmounting bosses (not shown) on a crankcase 33 (FIG. 2) of engine 32 andthe housing or transmission case of the geartrain. More particularly,and as shown in FIG. 4A, fasteners 36 a are received within the mountingbosses on engine 32 and fasteners 36 b couple CVT 34 to the geartrain.

With respect to FIGS. 2-10, CVT 34 includes a housing 40 having an innerportion or cover 42 and an outer portion or cover 44 removably coupledtogether. In one embodiment, inner cover 42 is comprised of a metallicmaterial, such as aluminum, and/or a polymeric material. Inner cover 42includes a peripheral surface 54 extending outwardly from a rear surface56. Peripheral surface 54 includes a sealing surface 60, illustrativelya lip, configured to couple with outer cover 44 using mechanicalfasteners 62. As shown in FIG. 8, inner cover 42 also may include adiverter plate or member 58 configured to direct air flow throughhousing 40, as disclosed herein. Diverter plate 58 may be removablycoupled to inner cover 42 with mechanical fasteners. Diverter plate 58may include a first portion 58 a positioned generally adjacent a driveclutch and a second portion 58 b positioned generally adjacent a portionof a driven clutch, as disclosed further herein.

In embodiments, as shown in FIG. 4B, CVT 34 may include a routing tray200 configured to be coupled to inner cover 42. More particularly,routing tray 200 is coupled to a forward extent of inner cover 42 with aplurality of fasteners 202 which are received within a plurality ofapertures 204 on inner cover 42. Routing tray 200 includes a forwardportion 206 positioned along the forward surface of inner cover 42 andan upper portion 208 positioned along the upper surface of inner cover42. In this way, routing tray 200 protects other components of vehicle 2in the event that a portion of CVT 34 fails. For example, if a componentof CVT 34 moves outward of housing 40 during a failure of CVT 34, thenrouting tray 200 prevents such components from contacting othercomponents and portions of vehicle 2.

Additionally, routing tray 200 includes at least one channel 207configured to receive a wire, tubing, pipe, or other conduit. In thisway, various conduits of vehicle 2 may be routed around a portion of CVT34 but not contact various portions of housing 40 of CVT 34.

Additionally, outer cover 44 may be comprised of a metallic materialand/or a polymeric material, such as an injection-moldable plastic. Asshown best in FIG. 7, and disclosed further herein, outer cover 44generally follows the shape and contour of the drive and driven clutcheswhich may increase air shear and improve heat transfer because the outersurface of outer cover 44 is closely positioned to the sheaves of thedrive and driven clutches.

Referring to FIGS. 2-5, CVT housing 40 includes a single air intake orinlet port 46 for receiving air to cool CVT 34 and a single air outletport 48 to exhaust warm or hot air from CVT 34. Illustratively, outercover 44 includes air inlet port 46 and inner cover 42 includes airoutlet port 48. Inlet port 46 is sealingly coupled to an intake duct 50to provide cooling, pre-filtered ambient air to CVT 34. As shown in FIG.3B, intake duct 50 may include a flexible coupler 51 at both endsthereof which allow for coupling and sealing the ends of intake duct 50to CVT 34 and a CVT intake port 53 of vehicle body 14 (FIG. 14). Intakeduct 50 itself is comprised of a rigid material which inhibits duct 50collapsing, folding, or otherwise deforming. Therefore, intake duct 50allow the openings at both ends of intake duct 50 to remain fullyexpanded and allow the maximum amount of air to enter CVT 34.Additionally, outlet port 48 is sealingly coupled to an outlet duct 52to expel hot air from CVT 34.

Referring now to FIGS. 5-7, CVT 34 includes a primary or drive clutch orpulley 70, a secondary or driven clutch or pulley 72, and a belt 74extending therebetween. Drive clutch 70 is rotatably coupled to acrankshaft (not shown) of engine 32. Driven clutch 72 is rotatablycoupled to an input shaft (not shown) of the geartrain and is rotatablycoupled to drive clutch 70 through belt 74. Belt 74 may be comprised ofa polymeric material, for example rubber, and may also includereinforcing members, such as metal cords or other reinforcing material.In one embodiment, belt 74 may be comprised of a metallic material, forexample, belt 74 may be a chain. In cross-section, belt 74 may generallydefine a “V” shape. Belt 74 is configured to contact drive clutch 70and, in one embodiment, expand in diameter in order to contact drivenclutch 72.

As shown in FIGS. 5-7, drive clutch 70 includes a moveable sheave 76positioned adjacent outer cover 44 of CVT 34 and a stationary sheave 78positioned adjacent diverter plate 58 of CVT 34. During operation of CVT34, stationary sheave 78 maintains a fixed position and does not moverelative to moveable sheave 76. Conversely, moveable sheave 76 of driveclutch 70 is configured for axial movement relative to stationary sheave78 in order to engage belt 74 and effect various drive ratios. The axialmovement of moveable sheave 76 occurs generally along an axis ofrotation thereof and in a direction perpendicular to longitudinal axis L(FIG. 1). Additional details of drive clutch 70 may be disclosed in U.S.Pat. No. 9,566,858, issued on Feb. 14, 2017 (Attorney Docket No.PLR-15-26601.01P) and U.S. patent application Ser. No. 15/388,106, filedDec. 22, 2016 (Attorney Docket No. PLR-06-27992.00P), the completedisclosures of which are expressly incorporated by reference herein.

Referring still to FIGS. 5-7, the rotation of belt 74 caused by driveclutch 70 drives driven clutch 72. Driven clutch 72 includes astationary sheave 80 positioned adjacent outer cover 44 and a moveablesheave 82 positioned adjacent inner cover 42. Stationary sheave 80 iscoupled to a shaft of the geartrain and maintains a fixed positionrelative to moveable sheave 82. Moveable sheave 82 may be configured foraxial translational movement along an axis of rotation thereof between aclosed position when adjacent stationary sheave 80 and an open positionin which moveable sheave 82 slides or otherwise moves axially apart fromstationary sheave 80. The movement of moveable sheave 82 engages belt 74in various configurations in order to effect various driving ratios forvehicle 2. Additional details of driven clutch 72 may be disclosed inU.S. Pat. No. 9,566,858, issued on Feb. 14, 2017 (Attorney Docket No.PLR-15-26601.01P) and U.S. patent application Ser. No. 15/388,106, filedDec. 22, 2016 (Attorney Docket No. PLR-06-27992.00P), the completedisclosures of which are expressly incorporated by reference herein.

During operation of CVT 34, drive clutch 70 engages belt 74 and whenbelt 74 engages driven clutch 72, driven clutch 72 rotates, which causesthe shaft of the geartrain to rotate. More particularly, drive clutch 70rotates with the crankshaft of engine 32 and the rotation thereof drivesrotation of driven clutch 72 through rotation of belt 74. Depending onthe operating conditions of vehicle 2, moveable sheaves 76, 82 of driveclutch 70 and driven clutch 72, respectively, may be moved relative tostationary sheaves 78, 80 to adjust driving ratios for vehicle 2. Duringmovement of moveable sheaves 76, 82, belt 74 is configured to movebetween a starting position and a high-ratio position. Movement ofmoveable sheaves 76, 82 may be electronically, mechanically, or fluidlycontrolled.

With respect to FIGS. 6A-10, as CVT 34 is operating, heat is generatedand the temperature within housing 40 increases. As such, it isnecessary to cool CVT 34 during operation thereof. In general, CVT 34 iscooled by providing ambient air within housing 40. Housing 40 and any ofsheaves 76, 78, 80, 82 may be specifically configured for increasedcooling. For example, as disclosed herein, the configuration of outercover 44 generally follows the contour of sheaves 76, 80 such that airshear and heat transfer are increased due to close positioning of outercover 44 relative to sheaves 76, 80. Illustratively, a distance 140 isdefined between the outermost surface of stationary sheave 80 of drivenclutch 72 and an innermost surface of outer cover 44 and distance 140 isequal at all portions of outer cover 44 adjacent stationary sheave 80 ofdriven clutch 72. In one embodiment, distance 140 may be approximately4-10 mm and, illustratively, is approximately 6 mm. Distance 140 may beoptimized to be the smallest distance between the outermost surface ofstationary sheave 80 of driven clutch 72 and the innermost surface ofouter cover 44 without allowing for any interference therebetween,thereby facilitating air flow through housing 40 and around stationarysheave 80.

As shown in FIG. 6A, with respect to the configuration of sheaves 76,78, 80, 82, at least some of sheaves 76, 78, 80, 82 have an increasedsurface area due to the inclusion of fins. Illustratively, at leaststationary sheave 78 of drive clutch 70 includes a plurality of fins 84extending radially outward from an axis of rotation R₁ of drive clutch70. More particularly, fins 84 extend outward from a body portion orouter sheave face 86 of sheave 78 in the direction of axis of rotationR₁ and extend radially therefrom. A first portion 88 of fins 84 has alength less than a length of a second portion 90 of fins 84. As shown inFIG. 6B, first portion 88 of fins 84 extends radially outwardly from alip 87 of outer sheave face 86 along a distance D₁, which is measuredfrom lip 87 to an apex 88A defining the radially-outermost surface offins 88. Similarly, as shown in FIG. 6C, second portion 90 of fins 84extends radially outwardly from lip 87 of outer sheave face 86 along adistance D₂, which is measured from lip 87 to an apex 90A defining theradially-outermost surface of fins 90. Distances D₁ and D₂ may beapproximately equal to each other or may be different such that distanceD₁ may be greater or less than distance D₂. In one embodiment, D₁ and D₂are 3-6 mm and, more particularly, are approximately 4-5 mm.Illustratively, both D₁ and D₂ may be approximately 4.9 mm. It may beappreciated that distances D₁ and D₂ do not extend radially outwardly toa position which would interfere with or contact inner cover 42 ofhousing 40.

In one embodiment, first portion 88 includes 18 fins 84 and secondportion 90 includes 18 fins 84. As such, stationary sheave 78 of driveclutch 70 may include a total of 36 fins 84. However, in otherembodiments, first and second portions 88, 90 may include differentand/or unequal numbers of fins 84 and stationary sheave 78 may include atotal number of fins 84 less than or greater than 36. In one embodiment,an angular distance between fins 84 may be approximately equal to orless than 15 degrees and, other embodiments, the angular distancebetween fins 84 may be approximately 6-10 degrees if the number of fins84 is increased. By including fins 84 on stationary sheave 78, thesurface area of sheave 78 is increased. In this way, the surface ofsheave 78 which may be exposed to ambient air entering housing 40 isincreased, thereby allowing for increased efficiencies when coolingstationary sheave 78 and when removing heat from belt 74.

Referring still to FIG. 6A, moveable sheave 82 of driven clutch 72 alsomay include a plurality of fins 92 extending radially outward in adirection perpendicular to an axis of rotation R₂ of driven clutch 72and extending laterally outward from a body portion or outer sheave face94 in the direction of axis of rotation R₂. It may be appreciated thatat least a portion of fins 92 extends laterally outward of a balancering 83 defining the outer diameter of moveable sheave 82 such that atleast a portion of fins 92 are proud of balance ring 83, as shown in atleast FIG. 15. Illustrative moveable sheave 82 may include a total of 12fins 92, however, moveable sheave 82 may include any number of fins 92.Fins 92 may be coupled together with a circumferentially-extending fin96. The combination of radially-extending fins 92 andcircumferentially-extending fin 96 increases the surface area ofmoveable sheave 82, thereby allowing for increased cooling thereof whenambient air enters housing 40 and removal of heat from belt 74.

As shown best in FIG. 5, stationary sheave 80 of driven clutch 72 alsoincludes a plurality of fins 98 extending radially outward in adirection generally perpendicular to axis of rotation R₂ (FIG. 6A) ofdriven clutch 72 and extending laterally outward from a body portion orouter sheave face 100 in the direction of axis of rotation R₂.Illustrative stationary sheave 80 may include a total of 12 fins 98,however, stationary sheave 80 may include any number of fins 98. Each offins 98 may extend continuously between a nose or bell portion 102 and aplanar portion 104 of outer sheave face 100. Fins 98 increases thesurface area of stationary sheave 80, thereby allowing for increasedcooling thereof when ambient air enters housing 40 and removal of heatfrom belt 74.

In addition to the increased surface area of at least sheaves 78, 80, 82through respective fins 84, 92, 98, the configuration of housing 40increases cooling efficiencies of CVT 34. More particularly, andreferring to FIGS. 7-10, outer cover 44 receives ambient air throughintake duct 50 and inlet port 46. Outer cover 44 includes a firstchannel 110 which directs air A toward a center portion of stationarysheave 80 of driven clutch 72. More particularly, first channel 110 isdefined as the area between fins 98 through which air A is propelledaway from the center of stationary sheave 80 such that fins 98 may fillwith air A in first channel 110 and evacuate air A about driven clutch72 in a radial direction once fins 98 rotate past air inlet port 46.Illustratively, as air A enters first channel 110 adjacent the center ofstationary sheave 80, air A flows radially outward through first channel110 and towards an upper portion of housing 40, as disclosed furtherherein. In this way, air A is configured to flow through first channel110 to cool at least stationary sheave 80 of driven clutch 72. Air Athen flows into a second channel 112 defined between a surface 142 ofouter cover 44 and inner cover 42 and between diverter plate 58 andinner cover 42. Additionally, driven clutch 72 may have a largerdiameter than drive clutch 70 such that driven clutch 72 may be able topump or otherwise drive or direct air A through housing 40 and towardsdrive clutch 70 for increased cooling at drive clutch 70.

As shown in FIGS. 8-10, second channel 112 is positioned generallyadjacent a portion of drive clutch 70 and, illustratively, is positionedgenerally adjacent stationary sheave 78 thereof. As shown in FIG. 10,air A flows in an inward direction normal to the page, as indicated bythe circled “X”, when flowing through second channel 112 towards driveclutch 70. It may be appreciated that inner cover 42 includes anextension member 64, as shown in FIGS. 8 and 9, which prevents incomingair A at a position adjacent outlet port 48 from flowing directly out ofhousing 40 through outlet port 48. Rather, extension member 64 directsincoming air A towards second channel 112. Second channel 112 promotesair flow from driven clutch 72 and towards drive clutch 70 by drawingair A from first channel 110 towards drive clutch 70 and directing air Aradially thereto. In this way, housing 40 is configured to allow air toflow between inner and outer covers 42, 44 and between drive clutch 70and driven clutch 72.

Air A then flows in a generally counterclockwise direction aboutstationary sheave 78 and is distributed about a center portion thereofto provide cooling air thereto, as indicated by the circled “dot” inFIG. 9, denoting air A flowing outwardly in a direction normal to thepage and towards the location of moveable sheave 76. Air A then flowstoward driven clutch 72 through a third channel 113 defined by diverterplate 58 such that air flow occurs between clutches 70, 72 and betweeninner and outer covers 42, 44. In this way, air A flowing into secondchannel 112 is distributed about stationary sheave 78 of drive clutch 70and then flows into third channel 113 which facilitates air flow towardsdriven clutch 72.

Air A at driven clutch 72 also may flow in a generally counterclockwisedirection and, in some embodiments, may join with air A initiallyentering housing 40 through channel 110. Additionally, air A may flowoutwardly towards moveable sheave 82 of driven clutch 72, as indicatedby the circled “dot” to join with other flow streams or paths of air A.When air A at driven clutch 72 circulates about stationary and moveablesheaves 80, 82 of driven clutch 72 and flows towards an upper portion ofinner cover 42, air A may exit housing 40 at portion or channel 114 andflow outwardly from housing 40 through outlet port 48 and outlet duct52.

To promote air A to flow counterclockwise about driven clutch 72,peripheral surface 54 of inner cover 42 is configured to increase indistance from driven clutch 72 in the direction of the flow of air A.More particularly, where air A flows from third channel 113 towardsdriven clutch 72, a distance D₃ between the radially-outermost surfaceof driven clutch 72 and the inner portion of peripheral surface 54 isless than a distance D₄, defined as the distance between theradially-outermost surface of driven clutch 72 and the inner portion ofperipheral surface 54 generally adjacent outlet port 48. By configuringperipheral surface 54 of inner cover 42 to increase in distance fromdriven clutch 72 in the counterclockwise direction, air A is guided orencouraged to flow in the counterclockwise direction to cool theentirety of driven clutch 72 and any hot air generally surroundingdriven clutch 72 is guided toward outlet port 48 to be expelled fromhousing 40. Therefore, the configuration of housing 40 and, inparticular, inner cover 42, promotes air flow about driven clutch 72 andguides hot air towards outlet port 48, thereby increasing coolingefficiency for CVT 34.

Referring to FIGS. 11A-20, vehicle 2 (FIG. 1) may include a powertrainassembly 30′ having an engine 32′ and a CVT 34. CVT 34′ may bepositioned laterally outward of engine 32′ and operably coupled toengine 32′ and a shiftable transmission 35 through a bell housing 160.Alternatively, CVT 34′ may be positioned longitudinally forward ofengine 32′ and extend laterally across a width of vehicle 2. In such aconfiguration, the drive clutch of CVT 34′ is positioned generally alonga front passenger or right side of vehicle 2 and the driven clutch ofCVT 34′ is positioned generally along a driver or left side of vehicle2. In one embodiment, the driven and drive clutches may be positioned onopposing sides of longitudinal axis L. However, in other embodimentswhere the majority or an entirety of CVT 34′ is positioned along oneside of longitudinal axis L, the driven and the drive clutches may bepositioned on the same side of longitudinal axis L.

As shown best in FIGS. 11A-11C, a bell housing 160 is integral withtransmission 35 and includes an opening 162 configured to allow couplingbetween the crankshaft (not shown) of engine 32′ and a drive clutch 70of CVT 34′. More particularly, a carrier bearing 164 is positionedintermediate bell housing 160 and the drive clutch and facilitatesappropriate coupling, alignment, and spacing between engine 32′ and CVT34′. Bell housing 160 may be utilized where, due to the configuration ofengine 32′ and/or transmission 35, CVT 34′ is spaced from engine 32′ bymore than a predetermined distance. As such, bell housing 160 isconfigured to support CVT 34′ at a location greater than thepredetermined distance from engine 32′ and provide the necessary spacefor a drive inlet or other component of powertrain assembly 30′.Additionally, the space between engine 32′ and CVT 34′ which is createdby bell housing 160 allows for air flow along an inner side of CVT 34′such that air can flow adjacent a drive clutch of CVT 34′, as disclosedfurther herein, to facilitate cooling of the drive clutch.

As disclosed herein, bell housing 160 is integral with transmission 35such that bell housing 160 is integrally formed with a housing oftransmission 35. Transmission 35 is configured to be operably coupledwith the driven clutch of CVT 34′ through an input shaft 166 oftransmission 35. In this way, rotational movement of the driven clutchis transferred to transmission 35 through input shaft 166. Transmission35 includes an internal gear set (not shown) which transfers movement toan output shaft 168 configured to be operably coupled to a rear drivemember (not shown) for providing motive power to rear wheels 8.Referring to FIGS. 11D and 11E, in embodiments, an alternative bellhousing 160′ is integral with transmission 35 which is coupled to drivenclutch 72′ of CVT 34′ through input shaft 166′ and is coupled to therear drive member through output shaft 168′. Transmission 35 also iscoupled to drive clutch 70′ of CVT 34′ through bell housing 160′. Moreparticularly, a carrier bearing assembly 164′ is partially receivedwithin an opening 162′ of bell housing 160′ and is coupled with driveclutch 70′.

Carrier bearing assembly 164′, as shown in FIG. 11E, includes a bearinghousing 210 having a nose 212 and a central aperture 214. A lip seal 216is received within nose 212 and includes a central aperture 218 which iscoaxial with central aperture 214. Carrier bearing assembly 164′includes a rolling element bearing 220 also with a central aperture 222coaxial with apertures 214, 218. A retention member 224, such as a “C”clip, is positioned within nose 212 and proximate rolling elementbearing 220 therein. Central apertures 214, 218, 222 are configured toreceive a portion of an axial shaft 226 which is configured to rotateabout an axis A to transmit rotational force between transmission 35 anddrive clutch 70′. Shaft 226 is received within a central aperture 230 ofa bearing 228, illustratively a roller bearing. Bearing 228 is retainedon shaft 226 with retention member 224 and a plurality of otherretention members, such as retention member 232 and retention member234. In embodiments, both retention members 232, 234 are spring membersand retention member 234 is a C clip. Additionally, a plate 236 may abutbearing 228 and further retain bearing 228 and retention members 232,234. A spring member 238 may be positioned proximate plate 236 and abuta portion of bearing housing 210.

It may be appreciated that portions of carrier bearing assembly 164′ arepositioned within the inlet of drive clutch 70′. For example, at leastnose 212 of bearing housing 210, rolling element bearing 220, andportions of axial shaft 226 are received within the inlet of driveclutch 70′ such that carrier bearing assembly 164′ positions bellhousing 160′ and transmission 35 as close to CVT 34′ as possible. Moreparticularly, at least portions of carrier bearing assembly 164′ arepositioned within housing 40′ of CVT 34′, thereby allowing CVT 34′ to bepackaged in close proximity to transmission 35 given that this area ofvehicle 2 tends to be crowded with additional components.

Because carrier bearing assembly 164′ positions CVT 34′ in closeproximity to bell housing 160′ and transmission 35, seal 216 isconfigured to prevent oil transfer to/from CVT 34′. More particularly,seal 216 includes a body portion 217 a and a flange or wiper 217 bcoupled to body portion 217 a and positioned at an axial end of bodyportion 217 a. At least wiper 217 b is comprised of a rigid material,for example a metallic material. Body portion 217 a has a serpentineconfiguration and is positioned with central aperture 214 of nose 212 ofbearing housing 210 while wiper 217 b is a generally linear member andis positioned axially outward of nose 212 such that wiper 217 b is insealing contact with shaft 226 and the axial end of nose 212. Bodyportion 217 a also includes at least one spring 219, illustrativelycomprised of a rigid material such as metal, as shown best in FIG. 11G,which is configured to apply pressure to the sealing lip of seal 216.More particularly, spring 219 maintains near constant and sufficientcompression of the lip seal interface of seal 216 to ensure propersealing as seal 216 and the shaft wears due to relative rotationalmotion over the life of the assembly. It may be appreciated that a seal240, having the same configuration as seal 216, may be positioned at theinterface of input shaft 166′ and bell housing 160′, as shown in FIG.11F.

Wiper 217 b of seal 216 (which is the same configuration for seal 240)is configured to prevent debris contact the sealing lip(s) of seal 216.For example, in the event of a failure of belt 74′, cord and debris maybecome entangled around shafts 166′ and/or 226 between sheave 84′ and/orsheave 94′ and adjacent seal 216, 240. During subsequent operation,relative motion between belt cord material and seal(s) 216, 240 generateenough heat and abrasion to potentially damage seal 216, 240. Thecontinued operation of sheaves 84′, 94′ create a vacuum which then couldallow oil transfer between CVT 34′ and transmission 35. However, theposition and configuration wiper 217 b relative to nose 212 and shaft226 prevents seal 216 from contacting cord and debris from failed belt74′ even if belt 74′ applies a pressure thereto.

During operation of transmission 35 and CVT 34′, as belt 74′ andmoveable sheave 76′ of drive clutch 70′ move relative to each other,belt 74′ may exert a force on stationary sheave 78′. This force could betransmitted to seal 216 and potentially push seal 216 such that seal 216moves out of position and creates a vacuum which allows oil transferbetween CVT 34′ and transmission 35. However, the position andconfiguration of wiper 217 b relative to nose 212 and shaft 226 preventsseal 216 from moving even if belt 74′ applies a pressure thereto. Assuch, wiper 217 b maintains the position of seal 216 on shaft 226. Moreparticularly, because wiper 217 b is positioned outwardly of nose 212and bearing housing 210 extends into housing 40′ of CVT 34′, wiper 217 bis exposed to the inside of housing 40′ and cannot be pushed intobearing housing 210 even if belt 74′ applies a pressure thereto.

Additionally, the diameter of nose 212 of carrier bearing assembly 164′is minimized by selecting a non-spherical rolling element bearing 220 toprovide an annular space for cooling air to enter through inlet port 46a to get to the center of stationary sheave 78′ of drive clutch 70′. Inthis way, the configuration of carrier bearing assembly 164′ allows forincreased cooling air to facilitate cooling of at least drive clutch 70′while also maintaining close proximity of CVT 34′ to transmission 35.

Referring now to FIGS. 12-14B, CVT 34′ includes a housing 40′ having aninner cover 42′ and an outer cover 44′ which are removably coupledtogether with mechanical fasteners. Housing 40′ may be configured asshown in FIG. 14A or as in FIG. 14B. In one embodiment, inner cover 42′is comprised of a metallic material, such as aluminum, and/or apolymeric material. Inner cover 42′ includes a peripheral surface 54′extending from a rear surface 56′. Peripheral surface 54′ includes asealing surface 60′, illustratively a lip, configured to couple withouter cover 44′ using mechanical fasteners 62′ (FIG. 13). As shown inFIG. 17, inner cover 42′ also may include a diverter plate or member 58′configured to direct air flow through housing 40′. Diverter plate 58′may be removably coupled to inner cover 42′ with mechanical fasteners.Diverter plate 58′ is generally positioned adjacent the drive clutch, asdisclosed further herein.

Additionally, outer cover 44′ may be comprised of a metallic materialand/or a polymeric material, such as an injection-moldable plastic. Asshown best in FIG. 16, and disclosed further herein, outer cover 44′generally follows the shape and contour of the drive and driven clutcheswhich may increase air shear and improve heat transfer because the outersurface of outer cover 44′ is closely positioned to the sheaves of thedrive and driven clutches.

Referring to FIGS. 12-14B, CVT housing 40′ includes a plurality of airintakes or inlet ports 46′ for receiving air to cool CVT 34′ and asingle air outlet port 48′ to exhaust warm or hot air from CVT 34′.Illustratively, housing 40′ includes two air inlet ports 46 a′ and 46b′, where a first air inlet port 46 a′ is positioned on inner cover 42′and a second air inlet port 46 b′ is positioned on outer cover 44′. Inone embodiment, first air inlet port 46 a′ (FIG. 13) is positionedadjacent the drive clutch and second air inlet port 46 b′ is positionedadjacent the driven clutch, thereby balancing the distribution of coolerambient air on both sides of the CVT belt. First inlet port 46 a′ issealingly coupled to a first intake duct 50 a′ positioned along innercover 42′ and second inlet port 46 b′ is sealingly coupled to a secondintake duct 50 b′ positioned along a portion of outer cover 44′.

Additionally, outlet port 48′ is sealingly coupled to an outlet duct 52′to expel hot air from CVT 34′. As shown in FIGS. 12-14B, outlet port 48′is positioned on inner cover 42′ at a position generally adjacent thedriven clutch and, in this way, inner cover 42′ of CVT 34′ includesfirst air inlet port 46 a′ positioned generally adjacent the driveclutch and outlet port 48′ positioned generally adjacent the drivenclutch. Illustratively, outlet port 48′ is not centered on the CVT belt,but rather, is biased or otherwise positioned inboard of at least aportion of the CVT belt towards rear surface 56′ of inner cover 42′.

Referring now to FIGS. 15 and 16, CVT 34′ includes a primary or driveclutch or pulley 70′, a secondary or driven clutch or pulley 72′, and abelt 74′ extending therebetween. Drive clutch 70′ is rotatably coupledto a crankshaft (not shown) of engine 32′ (FIG. 11A). Driven clutch 72′is rotatably coupled to an input shaft (not shown) of transmission 35and is rotatably coupled to drive clutch 70′ through belt 74′. Belt 74′may be comprised of a polymeric material, for example rubber, and mayalso include reinforcing members, such as metal cords or otherreinforcing material. In one embodiment, belt 74′ may be comprised of ametallic material, for example, belt 74′ may be a chain. Incross-section, belt 74′ may generally define a “V” shape. Belt 74′ isconfigured to contact drive clutch 70′ and, in one embodiment, expand indiameter in order to contact driven clutch 72′.

As shown in FIGS. 15 and 16, drive clutch 70′ includes a moveable sheave76′ positioned adjacent outer cover 44′ of CVT 34′ and a stationarysheave 78′ positioned adjacent inner cover 42′ of CVT 34′. Duringoperation of CVT 34′, stationary sheave 78′ maintains a fixed positionand does not move relative to moveable sheave 76′. Conversely, moveablesheave 76′ of drive clutch 70′ is configured for axial movement relativeto stationary sheave 78′ in order to engage belt 74′ and effect variousdrive ratios. The axial movement of moveable sheave 76′ may occurgenerally in a direction perpendicular or parallel to longitudinal axisL (FIG. 1). Additional details of drive clutch 70′ may be disclosed inU.S. Pat. No. 9,566,858, issued on Feb. 14, 2017 (Attorney Docket No.PLR-15-26601.01P) and U.S. patent application Ser. No. 15/388,106, filedDec. 22, 2016 (Attorney Docket No. PLR-06-27992.00P), the completedisclosures of which are expressly incorporated by reference herein.

Referring still to FIGS. 15 and 16, the rotation of belt 74′ caused bydrive clutch 70′ drives driven clutch 72′. Driven clutch 72′ includes astationary sheave 80′ positioned adjacent outer cover 44′ and a moveablesheave 82′ positioned adjacent inner cover 42′. Stationary sheave 80′ iscoupled to a shaft of transmission 35 (FIG. 11A) and maintains a fixedposition relative to moveable sheave 82′. Moveable sheave 82′ may beconfigured for axial translational movement between a closed positionwhen adjacent stationary sheave 80′ and an open position in whichmoveable sheave 82′ slides or otherwise moves axially apart fromstationary sheave 80′. The movement of moveable sheave 82′ engages belt74′ in various configurations in order to effect various driving ratiosfor vehicle 2. Additional details of driven clutch 72′ may be disclosedin U.S. Pat. No. 9,566,858, issued on Feb. 14, 2017 (Attorney Docket No.PLR-15-26601.01P) and U.S. patent application Ser. No. 15/388,106, filedDec. 22, 2016 (Attorney Docket No. PLR-06-27992.00P), the completedisclosures of which are expressly incorporated by reference herein.

During operation of CVT 34′, drive clutch 70′ engages belt 74′ and whenbelt 74′ engages driven clutch 72′, driven clutch 72′ rotates, whichcauses the shaft of transmission 35 to rotate. More particularly, driveclutch 70′ rotates with the crankshaft of engine 32′ and the rotationthereof drives rotation of driven clutch 72′ through rotation of belt74′. Depending on the operating conditions of vehicle 2, moveablesheaves 76′, 82′ of drive clutch 70′ and driven clutch 72′,respectively, may be moved relative to stationary sheaves 78′, 80′ toadjust driving ratios for vehicle 2. During movement of moveable sheaves76′, 82′, belt 74′ is configured to move between a starting position anda high-ratio position. Movement of moveable sheaves 76′, 82′ may beelectronically, mechanically, or fluidly controlled.

With respect still to FIGS. 15 and 16, as CVT 34′ is operating, heat isgenerated and the temperature within housing 40′ increases. As such, itis necessary to cool CVT 34′ during operation thereof. In general, CVT34′ is cooled by providing ambient air within housing 40′. Housing 40′and any of sheaves 76′, 78′, 80′, 82′ may be specifically configured forincreased cooling. For example, as disclosed herein, the configurationof outer cover 44′ generally follows the contour of sheaves 76′, 80′such that air shear and heat transfer are increased due to closepositioning of outer cover 44′ relative to sheaves 76′, 80′.Illustratively, a distance 140′ is defined between the outermost surfaceof stationary sheave 80′ of driven clutch 72′ and an innermost surfaceof outer cover 44′ and distance 140′ is not equal at all portions ofouter cover 44′ adjacent stationary sheave 80′ of driven clutch 72′.Rather, in one embodiment, distance 140′ may be approximately 6 mm at aposition adjacent bell portion 102′ of stationary sheave 80′ anddistance 140′ may be approximately 10 mm at a position adjacent planarportion 104′ of outer sheave face 100′ of stationary sheave 80′. Asshown best in FIG. 20, distance 140′ remains generally constant betweenthe outermost surface of stationary sheave 80′ of driven clutch 72′ andthe innermost surface of outer cover 44′ until a tapered region 180 ofouter cover 44′. At tapered region 180 of outer cover 44′, a distancebetween the innermost surface of outer cover 44′ and the outermostsurface of stationary sheave 80′ may increase.

As shown in FIG. 15, with respect to the configuration of sheaves 76′,78′, 80′, 82′, at least some of sheaves 76′, 78′, 80′, 82′ have anincreased surface area due to the inclusion of fins. Illustratively, atleast stationary sheave 78′ of drive clutch 70′ includes fins 84extending radially outward from an axis of rotation R₁ of drive clutch70′, as is similarly disclosed herein with respect to stationary sheave78 of FIGS. 6A-6C. By including fins 84 on stationary sheave 78′, thesurface area of sheave 78′ is increased. In this way, the surface ofsheave 78′ which may be exposed to ambient air entering housing 40′ isincreased, thereby allowing for increased efficiencies when coolingstationary sheave 78′ and removing heat from belt 74′.

Referring still to FIG. 15, moveable sheave 82′ of driven clutch 72′also may include a plurality of fins 92′ extending radially outward in adirection perpendicular to an axis of rotation R₂ of driven clutch 72′and extending outward from a body portion or outer sheave face 94′ inthe direction of axis of rotation R₂. Illustrative moveable sheave 82′may include a total of 36 fins 92′, however, moveable sheave 82′ mayinclude any number of fins 92′. In one embodiment, an angular distancebetween fins 92′ may be approximately equal to or less than 15 degreesand, other embodiments, the angular distance between fins 92′ may beapproximately 6-10 degrees if the number of fins 92′ is increased. Afirst portion 92 a′ of fins 92′ has a length less than a length of asecond portion 92 b′ of fins 92′. It may be appreciated that fins 92′ donot extend radially outwardly to a position which would interfere withor contact inner cover 42′ of housing 40′.

In one embodiment, first portion 92 a′ includes 18 fins 92′ and secondportion 92 b′ includes 18 fins 92′. As such, moveable sheave 82′ ofdriven clutch 72′ may include a total of 36 fins 92′. However, in otherembodiments, first and second portions 92 a′, 92 b′ may includedifferent and/or unequal numbers of fins 92′ and sheave 82′ may includea total number of fins 92′ less than or greater than 36. In oneembodiment, an angular distance between fins 92′ may be approximatelyequal to or less than 15 degrees and, other embodiments, the angulardistance between fins 92′ may be approximately 6-10 degrees if thenumber of fins 92′ is increased. By including fins 92′ on moveablesheave 82′, the surface area of sheave 82′ is increased. In this way,the surface of sheave 82′ which may be exposed to ambient air enteringhousing 40′ is increased, thereby allowing for increased efficiencieswhen cooling moveable sheave 82′ and removing heat from belt 74′.

As shown best in FIGS. 14A and 14B, stationary sheave 80′ of drivenclutch 72′ also includes a plurality of fins 98′ extending radiallyoutward in a direction perpendicular to axis of rotation R₂ (FIG. 15) ofdriven clutch 72′ and extending outward from a body portion or outersheave face 100′ in the direction of axis of rotation R₂. Illustrativestationary sheave 80′ may include a total of 36 fins 98′, however,stationary sheave 80′ may include any number of fins 98′. In oneembodiment, an angular distance between fins 98′ may be approximatelyequal to or less than 15 degrees and, other embodiments, the angulardistance between fins 98′ may be approximately 6-10 degrees if thenumber of fins 98′ is increased. Each of fins 98′ may extendcontinuously between a nose or bell portion 102′ and a planar portion104′ of outer sheave face 100′. However, illustratively, fins 98′include a first plurality of fins 98 a′ which extend continuously frombell portion 102′ to planar portion 104′ and a second plurality of fins98 b′ which have a radial distance less than that of first plurality offins 98 a′. Fins 98′ increase the surface area of stationary sheave 80′,thereby allowing for increased cooling thereof when ambient air entershousing 40′ and removing heat from belt 74′.

In addition to the increased surface area of at least sheaves 78′, 80′,82′ through respective fins 84′, 92′, 98′, the configuration of housing40′ increases cooling efficiencies of CVT 34′ and allows for increasedheat removal from belt 74′. More particularly, and referring to FIG. 16,inner cover 42′ receives ambient air through intake duct 50 a′ and inletport 46 a′ and outer cover 44′ receives ambient air through intake duct50 b′ and inlet port 46 b′. In this way, ambient air is provided tohousing 40′ at two locations through both inlet ports 46 a′, 46 b′ toincrease cooling to drive clutch 70′ and driven clutch 72′,respectively.

FIGS. 18A and 18B illustrate air flow through housing 40′, where FIG.18A illustrates air flow through housing 40′ of FIG. 14A and FIG. 18Billustrates air flow through housing 40′ of FIG. 14B. As shown in FIGS.18A-20, with respect to outer cover 44′, a first channel 110′ directsair A toward stationary sheave 80′ of driven clutch 72′. Air A isconfigured to flow through first channel 110′ to cool at leaststationary sheave 80′ of driven clutch 72′ and into a second channel112′ extending around the perimeter of outer cover 44′ to direct air Atowards drive clutch 70′. More particularly, second channel 112′ definesa continuously recessed portion of outer cover 44′ and may be configuredas a relief channel to relieve pressure that builds within outer cover44′ at a position adjacent drive clutch 70′. For example, if pressureincreases at a cover portion 45 (FIGS. 18A and 18B) of outer cover 44′at a position adjacent drive clutch 70′, second channel 112′ mayfacilitate relief of such pressure to allow for more efficient pumpingof air A through housing 40′. It may be appreciated that second channel112′ of FIG. 18B is deeper (i.e., has more lateral width) than secondchannel 112′ of FIG. 18A. Additionally, first channel 110′ of FIG. 18Bhas a more rounded configuration than first channel 110′ of FIG. 18A. Inthis way, first channel 110′ of FIG. 18B has less stepped surfaces thanthat of FIG. 18A which may increase air transfer closer to drive clutch72′.

During operation of CVT 34′, as air A enters housing 40′ through inletport 46 b′, fins 98′ on stationary sheave 80′ may fill with air Aflowing into first channel 110′ and then evacuate air in a radialdirection once fins 98′ rotate past first channel 110′, thereby movingair A about driven clutch 72′ and towards second channel 112′. It may beappreciated that inner cover 42′ includes a wall or extension member 126(FIGS. 18A and 18B), which short circuits incoming air A at a positionadjacent outlet port 48′ to prevent incoming air A from flowing directlyout of housing 40′ through outlet port 48′. Rather, extension member 126of FIGS. 18A and 18B directs incoming air A about driven clutch 72′.

As air A flows from first channel 110′ and within second channel 112′ ofouter cover 44′, air A flows from driven clutch 72′ to drive clutch 70′along an upper surface of outer cover 44′ and continues to flow withinsecond channel 112′ along a lower surface of outer cover 44′ where it isexhausted from housing 40′ through outlet port 48′ of inner cover 42′.In this way, air A flows into first channel 110′ from inlet port 46 b′on outer cover 44′ and the configuration of outer cover 44′ allows air Ato flow therein to cool both stationary sheave 80′ of driven clutch 72′and moveable sheave 76′ of drive clutch 70′.

Referring still to FIGS. 18A-20, with respect to inner cover 42′, athird channel 113′ directs air A toward stationary sheave 78′ of driveclutch 70′. Air A is configured to flow through third channel 113′ tocool at least stationary sheave 78′ of drive clutch 70′ and into afourth channel 116 extending around the perimeter of inner cover 42′ todirect air A towards driven clutch 72′. More particularly, fins 84′ onstationary sheave 78′ may fill with air A flowing into third channel113′ and then evacuate air in a radial direction once fins 84′ rotatepast third channel 113′, thereby moving air A about drive clutch 70′ andtowards fourth channel 116. As air A flows within fourth channel 116 ofinner cover 42′, air A flows from drive clutch 70′ to driven clutch 72′along a lower surface of inner cover 42′ and continues to flow withinfourth channel 116 along an upper surface of inner cover 42′ where it isexhausted from housing 40′ through outlet port 48′ of inner cover 42′.In this way, air A flows into third channel 113′ from inlet port 46 a′on inner cover 42′ and the configuration of inner cover 42′ allows air Ato flow therein to cool both stationary sheave 78′ of drive clutch 70′and moveable sheave 82′ of driven clutch 72′.

The configuration of housing 40′ includes a plurality of volutesconfigured to promote and direct air A to flow within housing 40′.Illustratively, housing 40′ includes at least three volutes including afirst volute 120, a second volute 122, and a third volute 124. Moreparticularly, as shown in FIGS. 18A, 18B, and 19, first volute 120 isdefined by the cooperation of inner and outer covers 42′, 44′ and,illustratively, is defined by the cooperation of second channel 112′ ofouter cover 44′ and fourth channel 116 of inner cover 42′. As shown,first volute 120 is positioned adjacent a lower portion of inner andouter covers 42′, 44′ at a location generally adjacent drive clutch 70′.First volute 120 is configured to pump or otherwise drive air A towardsa center portion of driven clutch 72′ through channels 112′, 116. Inthis way, first volute 120 allows air therein to cool driven clutch 72′rather than merely flowing past it to increase cooling of at least thecenter portion of driven clutch 72′.

Additionally, and as shown in FIGS. 18A, 18B, and 20, housing 40′includes second volute 122 which is defined by the cooperation of innerand outer covers 42′, 44′ and, illustratively, is defined by thecooperation of second channel 112′ of outer cover 44′ and fourth channel116 of inner cover 42′. As shown, second volute 122 is positionedadjacent an upper portion of inner and outer covers 42′, 44′ at alocation generally adjacent driven clutch 72′. Second volute 122 isconfigured to pump or otherwise drive or distribute air A towards driveclutch 70′ through channels 112′, 116. As shown in FIG. 18B, secondvolute 122 may have a less stepped surface than second volute 122 ofFIG. 18A.

As is also shown in FIGS. 18A and 18B, housing 40′ includes third volute124 defined within a lower portion of inner cover 42′ along an inboardportion of fourth channel 116. Illustratively, third volute 124 ispositioned generally adjacent driven clutch 72′ and outlet port 48′ andis configured to pump or otherwise drive or direct hot air A withinhousing 40′ outwardly through outlet port 48′ and outlet duct 52′.

In addition to volutes 120, 122, 124 for directing air A through housing40′, at least moveable sheave 82′ of driven clutch 72′ includes awindage plate 128 coupled thereto, as shown best in FIGS. 15 and 20.More particularly, windage plate 128 may be coupled to fins 92′. Windageplate 128 is configured to promote cooling to at least moveable sheave82′ by pulling air A through a center opening 130 thereof to allow forefficient cooling of moveable sheave 82′ when at different axialpositions. It may be appreciated that sheaves 76′, 78′, and/or 80′ alsomay include a windage plate or similar feature to promote furthercooling thereof. For example, a windage plate 170 also may be includedon stationary sheave 78′ of drive clutch 70′, as shown in FIG. 15.

Additional details of vehicle 2 and/or the powertrain assembly may bedisclosed in U.S. patent application Ser. No. 15/388,436, filed Dec. 22,2016 (Attorney Docket No. PLR-15-27200.00P); U.S. patent applicationSer. No. 15/388,106, filed Dec. 22, 2016 (Attorney Docket No.PLR-06-27992.00P); and U.S. Patent Application Ser. No. 62/613,796,filed Jan. 5, 2018 (Attorney Docket No. PLR-15-28340.01P), the completedisclosures of which are expressly incorporated by reference herein.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

What is claimed is:
 1. A continuously variable transmission (“CVT”) fora vehicle, comprising: a drive clutch; a driven clutch operably coupledto the drive clutch; and a housing generally surrounding the drive anddriven clutches, the housing including an inner cover and an outer coverremovably coupled to the inner cover, and a radial distance between aperipheral surface of the inner cover and a radially-outermost surfaceof the driven clutch increases in a direction of air flow.
 2. The CVT ofclaim 1, wherein a first distance between a lower portion of theperipheral surface and the radially-outermost surface of the drivenclutch is less than a second distance between an upper portion of theperipheral surface and the radially-outermost surface of the drivenclutch.
 3. The CVT of claim 1, wherein the direction of air flow iscounterclockwise.
 4. The CVT of claim 1, wherein the radial distance isminimized along a lower portion of the inner cover.
 5. The CVT of claim4, wherein the radial distance is maximized along an upper portion ofthe inner cover.
 6. The CVT of claim 1, wherein the housing includes atleast two of a first volute generally adjacent the drive clutch andconfigured to direct air toward the driven clutch, a second volutegenerally adjacent the driven clutch and configured to direct air towardthe drive clutch, and a third volute generally adjacent the drivenclutch and configured to direct air toward an outlet of the housing. 7.The CVT of claim 1, wherein the driven clutch includes a moveable sheaveand a stationary sheave, and the stationary sheave is defined by a bellportion and an outer sheave face extending radially outward from thebell portion, and the bell portion includes a first plurality of finsextending longitudinally outward therefrom and the outer sheave faceincludes a second plurality of fins extending radially outwardtherefrom, and a number of fins defining the second plurality of fins,and at least a first portion of the second plurality of fins has alength less than that of a second portion of the second plurality offins.
 8. A continuously variable transmission (“CVT”) for a vehicle,comprising: a drive clutch including a moveable sheave and a stationarysheave; a driven clutch operably coupled to the drive clutch andincluding a moveable sheave and a stationary sheave; and a housinggenerally surrounding the drive and driven clutches and including asingle air inlet and a single air outlet, and the housing beingconfigured to flow air from a position adjacent the stationary sheave ofthe driven clutch to a position adjacent the stationary sheave of thedrive clutch.
 9. The CVT of claim 8, wherein the housing includes aninner cover having the single air outlet and an outer cover having thesingle air inlet and removably coupled to the inner cover, and the outercover includes a first channel positioned adjacent the stationary sheaveof the driven clutch and configured to flow air into a second channelpositioned adjacent the stationary sheave of the drive clutch, and thesecond channel is included within the inner cover.
 10. The CVT of claim9, further comprising a diverter plate, and the second channel isdefined by the diverter plate and the inner cover.
 11. The CVT of claim9, wherein the housing includes a third channel configured to receiveair adjacent the drive clutch and direct the air from adjacent the driveclutch towards the driven clutch.
 12. A continuously variabletransmission (“CVT”) for a vehicle, comprising: a drive clutch includinga moveable sheave and a stationary sheave; a driven clutch operablycoupled to the drive clutch and including a moveable sheave and astationary sheave; and a housing generally surrounding the drive anddriven clutches and including an inner cover and an outer cover, and theouter cover includes a channel configured to direct air toward the driveclutch.
 13. The CVT of claim 12, wherein the channel is configured todirect towards the stationary sheave of the drive clutch at a positionwithin the inner cover.
 14. The CVT of claim 13, wherein the inner coverincludes a diverter member positioned adjacent the stationary sheave ofthe drive clutch and configured to direct air from the channel towardthe stationary sheave.